Membranes consist of two layers of phospholipids, or a phospholipid bilayer. When the phospholipid molecules are put together, these chemical properties cause the molecules to quickly rearrange so all Hydrophobic tails are together in the center, away from the surrounding water molecules, and all Hydrophilic heads are facing out on both sides of the membrane.
None of the phospholipid molecules are bound together, and so they continually move around the cell surface membrane. They cannot leave the double layer due to their Hydrophobic tails. This is called the Fluid Mosaic model because the molecules are free to move, similar to water particles on the surface of a pond.
The chemical properties of the phospholipid bilayer effectively block both polar and non-polar molecules from entering the cytoplasm of the cell. However, the cell still has a method to exchange materials with its environment: Proteins.
Integral Proteins are embedded in the phospholipid molecules
→ Interact with the cytoplasm & external molecules outside the cell
Peripheral Proteins are attached to the surface
→ Interact with the phosphate heads
The 2 other features of the plasma membrane are :
Glycoproteins : proteins with a carbohydrate group attached to them
Cholesterol : a large molecule positioned between the tails of the phospholipid
→ reduces fluidity & permeability
When the cell membrane breaks, cellular lysis occurs and the insides of the cell are released into the outside environment.
Functions of Membrane Protiens:
Integral Proteins - interact with the cytoplasm inside the cell and the molecules outside the cell
Peripheral Proteins - interact with the phosphate heads
Glycoproteins - cell to cell recognition, the ability of cells to recognize what the other cell is
Cholesterol - helps to build and maintain the membranes
Work Cited :
"2.4 Membranes." Bio IBID Textbook. 21-22. PDF file.
Yang, Na Yeong. "The Cell Surface Membrane." 15 Mar. 2010. Grade 9 One Note Document file.
Membranes consist of phospholipid molecues, which are made up of a phosphate head, and two fatty acid tails.
A phospholipid molecule is composed of 2 main parts :
- Hydrophilic (hydros = "water" + philia = "love") Head → ATTRACTS water
- Hydrophobic (hydros = "water + phobos = "fear") Tail → REPELS water
Membranes consist of two layers of phospholipids, or a phospholipid bilayer. When the phospholipid molecules are put together, these chemical properties cause the molecules to quickly rearrange so all Hydrophobic tails are together in the center, away from the surrounding water molecules, and all Hydrophilic heads are facing out on both sides of the membrane.None of the phospholipid molecules are bound together, and so they continually move around the cell surface membrane. They cannot leave the double layer due to their Hydrophobic tails. This is called the Fluid Mosaic model because the molecules are free to move, similar to water particles on the surface of a pond.
The chemical properties of the phospholipid bilayer effectively block both polar and non-polar molecules from entering the cytoplasm of the cell. However, the cell still has a method to exchange materials with its environment: Proteins.
The 2 other features of the plasma membrane are :
When the cell membrane breaks, cellular lysis occurs and the insides of the cell are released into the outside environment.
Functions of Membrane Protiens:
Work Cited :
"2.4 Membranes." Bio IBID Textbook. 21-22. PDF file.
Yang, Na Yeong. "The Cell Surface Membrane." 15 Mar. 2010. Grade 9 One Note Document file.